High tensile splice



Dec. 15, 1964 R. F. coBAuGH HIGH TENSILE SPLICE Original Filed Sept. 15, 1959 United States Patent Oiitlce Re. 25,698 Reissued Dec. 15, 1964Lk 25,698 HIGH TENSLE SPLICE Robert F. Cobaugh, Hershey, Pa., assigner to AMP Incorporated, Harrisburg, Pa.

Griginal No'. 3,052,750, dated Sept. 4, 1962, Ser. No. 840,065, Sept. 1S, 1959. Application for reissue June 29, 1964, Ser. No. 390,255

7 Claims. (Cl. 174-90) Matter enclosed in heavy brackets appears in the original patent but forms no part of this reissue specilication; matter printed in italics indicates the additions made by reissue.

In the transmission of electrical energy, it is common to use a conductor comprised of a plurality of braided strands of aluminum wire, with a central steel wire or core disposed longitudinally. The steel strand vincreases the tensile strength of the conductor considerably. One of the ditlculties in using this type of wire is the problem of terminating it or joining two of these wires together. It is an object of this invention to provide a new and irnproved termination for such wires whereby the ends may be joined together quite easily with a mini-mum of effort.

Itis `an object of this invention to provide a means for joining steel stranded conductors together by coldforging a ferrule thereto. It is also an object of this invention to provide such a connection whereby a plurality of frangible inserts are ruptured and broken into small pieces during the crimping operation to key the ferrule and conductor together. These inserts may be externally notched to cause the insert to crack in predetermined areas and be embedded into the connector. This application constitutes a continuation-impart of my previously filed application, Serial No. 821,181, tiled June 18, 1959, now abandoned. f

Gther objects and attainments of the present invention will become apparent to those skilled in the art upon a reading of the following detailed description when taken in conjunction with the drawings in which there is shown and described an illustrative embodiment of the invention; it is to be understood, however, that this embodiment is not intended to be lexhaustive nor limiting of the invention but is given for purposes of illustration in order that others skilled in the art may fully understand the invention and the principles thereof and the manner of applying it in practical use so that they may modify it in various forms, each as 'may be best suited to the conditions of a particular use.

l In the drawings:

FIGURE 1 is a perspective View of a connecting means illustrating principles of this invention;

FIGURE 2 is a View similar to FIGURE 1 with the outer sleeve partially broken away;

FIGURE 3 is a partially cutaway perspective View of one of the inserts;

FIGURE 3A is a view similar to FIGURE 3 illustrating another embodiment of a suitable insert;

FIGURE 4 is a View illustrating the connector of FIG- URE 1 crimpedA onto a pair of conductors joining them together;

FIGURE 5 is a sectional view showing conductors situatcdwithin the connector prior to crimping; [and] FIGURE 6 is a sectional view taken along plane 6-6 [of FIGURE 4] of FIGURE 4; and

FIGURE 7 is a sectional view of an alternative embodiment showing conductors situated within the connector prior to crimping. l v

As shown in FIGURE 2, the connector includes an outer metal ferrule 10 (preferably of aluminum), with a plurality of inserts disposed within the ferrule 1i). The prefer-ment includes two inserts 11 positioned `adjacent. to each other and disposed on opposite sides of the midportion of the ferrule. ferrule 16 serve to locate the inserts and retain them in position. K

The inserts shown in the preferred embodiment are identical and comprise arcuate members 13 (FIGURE 3) having grooves or ser-rations 14 on the inside surface. Advantageously these inserts may be made of powdered metal which is easily manufactured, very hard and highly frangible. (The term powdered metal refers to objects made by the powdered metallurgical process. A suitable coinposition includes 97.15% Fe, 2% Cu, .85% C; cf. Physical Properties ot Reduced Iron Powder Plus Graphite and Copper, by George Stern, published in The Iron Age, March 24, 1949). This internal diameter is slightly larger than the steel core ofthe conductor that it is designed to accommodate. A pair of discs 16 have a central aperture 18 adapted to permit passage of the central core of the conductor therethrough. Arcuate slots 20 in the discs accommodate flanges 22 on the arcuate members 13. These slots are disposed at from each other. The insert is assembled by disposing the discs parallel to each other with the slots 20 aligned. The anges are forced iitted into their respective slots. The arcuate members 13 form less than a complete cylinder so that openings are disposed between each of the members 13 in assembled position. Notches Z1 in the edge of the discs 16 correspond with the openings between the members 13. Grooves 23 are impressed circurnterentially into the outside surface of the members 13 at regular intervals along the axial length of insert.

Another` embodiment of a suitable insert is shown in FIGURE 3A. An integral cylindrical member 16 with longitudinal slots 17 disposed along the outer surface of the insert. A central aperture 19' contains internal serrations 29'. The illustrated embodiment shows slots 17 forming quadrants of 90.

When it is desired to crimp a pair of conductors 24 having a central steel core 26 therein, the conductors are prepared by severing a length from the outer strands so that the core projects theretrom (note FIGURE 5). The conductor is inserted into one end of the fermle until the end of the strands abut the outer end of the first insert. The central steel core is threaded internally oi` the inserts and projects through the inserts into the center of the connector. The other conductor is prepared in a similar manner and is inserted into the opposite end of v pieces of the inserts bite intothe outer aluminum fer-` rule and the inner steel core. This biting action is assisted by the serrations 14 on the inside of the inserts.

Additional crimps on the outside of the ferrule secure the ferrule to the strands of the conductor. The other conductor is also joined in a similar fashion. As shown in the drawings, nine crimps on each side of the connector are suiiicient to crimp a size 1/0 wire. This is in lcontrast to the prior art devices vwhich require approximate-.ly vthirty-two crimps on each side for this size wire.

The embodiment of FIGURE 7 includes two inserts 1l positioned adjacent to each other and disposed on one side of the mid-portion of ferrule 10', and two more nserls 1l' likewise disposed on the opposite side. These inserts in FIGURE 7 are identical and take the form of FIGURE 3a.

A plurality of indents 12 in the When it is desired to crimp a pair of conductor 24 zaving a central steel core 26 therein, the central steel fore is threaded internally of the inserts and projects hrongh the inserts into the center of the connector. The tther'condactor is inserted into the opposite end of the Eerrate with the steel core projecting through the correvponeling inserts.

A plurality of crimps are then impressed n each end if `the ferrule in the manner shown in FIGURE 6, the rrumbled pieces of the inserts bite into the outer aluminum :er-rule and the inner steel core. This biting action is tssisted by serrations 20 on the inside of the inserts.

Thus, the device disclosed herein permits a crimped :onnection through an aluminum ferrule to a material vhich is harder than the aluminum, e;g. steel. Also, t permits termination through aluminum to metals re- ;uiring crimping pressures above 80,000 p.s.i. into a 'ange of 20),300 p.s.i. Although these extreme pres- Kures are employed, the size of the connector has been 'educed to about one-third the size of connectors emiloyed in the prior art in similar circumstances.

Changes in construction will occur to those skilled n the art and various apparently dierent modications md embodiments may be made Without departing from he scope of the invention. The matter set forth in the 'oregoing description and accompanying' drawings is )tiered by Way of illustration only. The actual scope of he invention is intended to be deined in the following :laims when viewed in their proper perspective against he prior art.

Iclaim:

1. A device for connecting electrical conductors having Lt least one` steel strand, comprising an aluminum f errule, L plurality of cylindrically coniigured' inserts made of highy frangible powdered metal within the ferrule, said inserts rroviding a central aperture adapted to accommodate the teel strand, a plurality of serrations in said inserts, said nserts adapted to be fractured into small pieces upon the tpplication or crimping pressure to the outside of the tluminum ferrule.

2. The device of claim 1 including radial slots in the alter surface of said inserts and running longitudinally if said inserts.

3. The device of claim l wherein the inserts are formed ay arcuate members spacedV from each other about a ommon axis.

4. The device of claim 1 wherein the inserts are formed 1y a pair of parallel circular discs with arcuate members itted into the discs at spaced intervals and notches in he discs corresponding to the spaces between the memers.

5. A connection between a pair of wires of the type having braided conductive strands and a cent-ral steel core including an outer aluminum ferrule, a plurality of metal inserts made of highly frangible powdered metal, said inserts having longitudinal slots radially therein on the outside surface, the steel core of the conductor disposed within the inserts, said inserts ruptured into small pieces and crimped to said steel core, said aluminum errule also crimped in the vicinity of the inserts, and saidl aluminum errule crimped onto the outer braided conductors'.

6. A device for connecting a pair of steel core stranded conductors including an outer aluminum ferrule, a pair of inserts made of highly frangible powdered metal disposed within the aluminum ferrule adjacent the centerpoint, a similar pair of inserts disposed on the opposite side of the centerpoint, the steel core of a conductor within one insert, the stranded portion of the conductor within the ferrule, a second' conductor similarly disposed on the opposite inserts, 'and crimped sections along cach insert serving to crumble the inserts and causing them to bite into the steel conductor and the inside surface of the cuter aluminum ferrule, and additional crimped sections crirnuing the aluminum ferrule to the stranded conductors.

7. A device for connecting an electrical conductor having at least one steel strand, comprising an aluminum ferrule, a plurality of cylindrically contigured inserts within-the ferrule, said inserts 1being formed by a pair of parallel circular disks-With radial notches therein, a plurality of arcuate members made trom highly frangible powdered metal, iitted into the notches in the disks to form radial slots in the outer surface of said inserts running longitudinally of said inserts, said insertspr viding a central aperture adapted to accommodate the' steel strands,- a plurality of serrations inl said insert and said inserts adapted to be com-pletelyfractured upon the application of crimping pressure to the outside of said ferrule.v

References Cited by the Examiner The following references, citedv by the Examiner, are of record in the patented tile of this patent or the original patient. l

UNITED STATES PATENTS 2,251,189 7/ 41 Jensen. 2,279,677 4/ 42 Heinrich 174-94 FOREIGN PATENTS 561,859 7/44 Great Britain.

JOHN F. BURNS, Primary Examiner.

E. JAMES SAX, Examiner. 

